Referring to FIG. 1, a normal healthy artery wall includes layers of tissue, such as the innermost intima 111, the media 107, the adventitia 103, and the periadventitia 101. The intima 111, media 107, and adventitia 103 are separated by two elastic membranes. The inner membrane is the internal elastic lamina (IEL) 109, which separates the intima 111 from the media 107, and the outer membrane is the external elastic lamina (EEL) 105, which separates the media 107 from the adventitia 103.
Coronary artery disease (CAD) and Peripheral artery disease (PAD) are both caused by the progressive narrowing of the blood vessels most often caused by atherosclerosis, the collection of plaque or a fatty substance along the inner lining or intima of the artery wall. Over time, this substance hardens and thickens, which can cause an occlusion in the artery, completely or partially restricting flow through the artery. Blood circulation to the arms, legs, stomach and kidneys brain and heart may be reduced, increasing the risk for stroke and heart disease.
Peripheral artery disease (PAD) and coronary artery disease (CAD) affect millions of people in the United States alone. PAD and CAD are silent, dangerous diseases that can have catastrophic consequences when left untreated. CAD is the leading cause of death in the United States while PAD is the leading cause of amputation in patients over 50 and is responsible for approximately 160,000 amputations in the United States each year.
Interventional treatments for CAD and PAD may include endarterectomy and/or atherectomy. Endarterectomy is surgical removal of plaque from the blocked artery to restore or improve blood flow. Endovascular therapies such as atherectomy are typically minimally invasive techniques that open or widen arteries that have become narrowed or blocked. Other treatments may include angioplasty to open the artery. For example, a balloon angioplasty typically involves insertion of a catheter into a leg or arm artery and positioning the catheter such that the balloon resides within the blockage. The balloon, connected to the catheter, is expanded to open the artery. Surgeons may then place a wire mesh tube, called a stent, at the area of blockage to keep the artery open.
During interventional treatments, trauma often occurs to the IEL 109, media 107, EEL 105, and adventitia 103. Trauma to the EEL 105 and/or adventitia 103 can initiate a severe inflammatory response, which can accelerate scarring and cause potential closure of the vessel.
Disruption of the EEL 105 can also signal complimentary and inflammatory factors that accelerate and further promote restenosis. Accordingly, an interventional treatment that avoids trauma to EEL 105, and thus to the adventitia 103, is desired.